LONG-TERM EFFECTS OF RADIATION FOR MEDULLOBLASTOMA ON INTELLECTUAL AND PHYSICAL DEVELOPMENT - A CASE-REPORT OF MONOZYGOTIC TWINS

Background. Recent advances in treatment have improved the prognosis f or medulloblastoma. Although postoperative radiation of the central ne rvous system (CNS) is widely practiced, late radiation sequelae, espec ially in long-term survivors, pose a constant risk. Methods. To assess the long-term effects of CNS radiation, a monozygotic twin girl with medulloblastoma was compared with her normal twin. Treatment included total removal of the mass, postoperative chemotherapy, and CNS radiati on with 47.8 Gy directed to the posterior fossa, 30.2 Gy to the cerebr al hemispheres, and 20 Gy to the whole spine. Results. Not only the ra diated patient's spine but also the unradiated upper and lower limbs w ere shorter than the control subject's. The patient's thyroid hormone level was within normal range; however, thyroid-stimulating hormone wa s higher than normal. The patient's intellectual ability deteriorated, and cognitive dysfunction has not improved as of 6 years after treatm ent. Conclusions. Treatment systems that do not cause late sequelae af fecting physical and intellectual development should be pursued.